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Fertilizers have been given significant attention due to their critical need for agriculture yield to meet the demand for food growth arising from population growth. The demand for potassium fertilizer (metric tons of K 2 O) has increased by 12% between 2015 and 2020. Therefore, the concern about the limited availability of soluble potassium resources in the southern hemisphere has become a key research focus for identifying alternative resources and technologies. This study presents a review of the fundamental knowledge of alternative technologies, such as acid leaching, hydrothermal and molten salt technology, as well as different alternative K-bearing silicate resources (ultrapotassic syenite, nepheline syenite, glauconitic sandstone and mica). Studies on fluxing agents proposed for the extraction of K+ based on different methods were analysed and compared. This paper offers a detailed overview of experimental kinetic analysis, kinetic and mechanism reactions, aims to improve the extraction technology and address relevant industry challenges. This review also reports on thermodynamic analysis of the mineral-salt/acid/alkaline systems, providing insights into the basis of industrial applications. Finally, the review provides opportunities and challenges of each technique and has shown that further techno-economic and process analysis are required to better identify the viability of each technique for large-scale industrial demonstration. [ABSTRACT FROM AUTHOR]

More than 70% of the potash fertilizer globally is produced by the froth flotation process, in which 4-dodecylmorpholine (DMP) serves as a reverse flotation agent. As the potash fertilizer production rapidly rises, the increased DMP levels in discharged brine pose a threat to the production of high-value chemicals. In this paper, composite particles of basic magnesium sulfate@TiO2 (BMS@TiO2) were prepared using a simple and mild loading method. These particles were utilized for the adsorption and photocatalytic degradation of DMP in brine. Compared with normal powdered materials, the granular BMS@TiO2 in this study can be easily separated from liquid, and the degradation intermediates will not enter the brine without causing secondary pollution. BMS@TiO2 consists of 5·1·7 phase (5Mg(OH)2·MgSO4·7H2O) whisker clusters embedding 2.3% TiO2. The adsorption equilibrium of DMP on BMS@TiO2 particles was achieved through hydrogen bonding and pore interception with the adsorption capacity of approximately 5 mg g−1 after 6 h. The photodegradation efficiency of DMP adsorbed on BMS@TiO2 reached about 92% within 16 h, which is compared with that of pure TiO2 nanoparticles. Additionally, excellent stability and recyclability of BMS@TiO2 were also observed in five cycle tests of adsorption and photocatalytic degradation of DMP, and the possible photocatalytic degradation pathways and mechanism of DMP are proposed following molecular electrostatic potential analysis. This work provides a sustainable and environmentally friendly approach for eliminating organic micropollutants from water environments. [ABSTRACT FROM AUTHOR]

In the context of the Chinese government's policy guidance, there is black soil protection and ecological environment protection. The purpose of this paper is to solve the problem that the soil ecology of the black soil in Northeast China is changing year by year, and it is necessary to explore the sowing and fertilization strategy under the new situation; most Chinese growers rely excessively on their personal experience in the process of soybean sowing and fertilization. In this study, we used "Heihe 43" soybeans and used regression experimental design methods to analyze the effects of planting density, nitrogen, phosphorus, and potassium fertilizer application on soybean yield and to determine the optimal planting density and fertilizer ratios. The study reveals that the optimal soybean planting density in Northeast China is 45.37 × 104 plants/ha, with nitrogen at 98.4 kg/ha, phosphorus at 218.96 kg/ha, and potash at 47.62 kg/ha. Under these conditions, soybean yields can reach 3816.67 kg/ha. This study can provide a theoretical method for decision-making to obtain the optimal planting density and fertilizer ratio for different regions of the farming system. [ABSTRACT FROM AUTHOR]

Rhubarb is a popular food in Europe due to the purgative action. Cultivation is the key way to ensure sustainable development and utilization of this herbal plant. In this paper, standardized cultivation of Rheum tanguticum (a kind of rhubarb) was explored through a three-year field experiment which investigated the effect of phosphorus (P) and potassium (K) fertilizer on growth indexes, sennoside content of R. tanguticum at different harvesting stages. Results showed that P and K fertilizer significantly increased root length, root diameter and root fresh weight, the maximum root fresh weight was 894.22 g/plant. Sennoside content of three-year-old R. tanguticum applied K fertilizer was over 5.87% at each harvesting stage in the third growth cycle and it increased along with growing year. Sennoside content has no obviously increment at the same harvesting stage, it also has no positive correlation with different harvesting stages and the wilting stage > green stage > growth stage in the same year. This study demonstrated that P and K fertilizer had accelerated effect on growth of R. tanguticum at the same harvesting stage, but had no obvious influence on the sennoside content. This will provide experimental data and guidance for the standardized cultivation of R. tanguticum. The effect of different fertilizer (P, K) doses, harvesting stages and growth years on growth indexes and sennosides contents of R. tanguticum was firstly explored. A modified HPLC detective method was developed to quantify the sennosides content of R. tanguticum. The effect of different fertilizer doses on growth indexes of R. tanguticum was firstly explored. Variation of sennoside content after applying fertilizers was firstly explored. The effect of harvesting stages on growth indexes and sennosides contents was firstly explored. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to clarify the expression pattern and molecular regulation mechanism of genes related to sugar, lipid and protein metabolism in maize ear leaves under different fertilization in field conditions. [ Method] Maize cultivar 'Luyu 16' was used as the material and five treatments were set up: No fertilizer (CK), nitrogen fertilizer ( N), N + P fertilizer (NP), N + K fertilizer ( NK) and N + P + K fertilizer ( NPK). At grain filling stage, the upper part of ear leaves was harvested for transcriptome analysis using RNA-Seq techniques. The differentially expressed genes ( DEGs) under different fertilizer treatments were analyzed by Hisat2 software. [Result]GO(Gene ontology)analysis showed that DEGs related to sugar, lipid and protein metabolism were enriched in Biological process ( BP), Cell components( CC) and Molecular function( MF). Although the enriched items were the same, the number of DEGs varied under different combinations. KEGG ( Kyoto encyclopedia of genes and genomes) analysis exhibited that more DEGs were enriched in carbon metabolism, starch and sucrose metabolism, and amino acid synthesis pathways. The total number of DEGs with both I log2 FC I > 1 and P < 0. 05 involved in sugar, lipid and protein metabolism under different fertilizer treatments was 82, 29 and 84, respectively. Among them, the total number of DE Gs with I log2 FC I > 2 was 6, 24 and 17. The number of DE Gs showed the maximum in comparisons of NPvsCK and NPKvsCK but the minimum in NvsCK comparison. Further analysis of DEGs with I log2 FC I showed that these DEGs had significant differences in the expression level and expression patterns. [ Conclusion] The combined of nitrogen, potassium and phosphorus fertilizer significantly affected the transcription levels of genes related to sugar, lipid and protein amino acids metabolism in maize ear leaves. Some key genes participating in the three organic substances' metabolism were identified. The results provided molecular basis for improving the photosynthetic efficiency of maize leaves by rational fertilization in the future. [ABSTRACT FROM AUTHOR]

Red mud and coal fly ash (CFA) are bulk aluminum-containing solid waste in the industrial production process, posing a great threat to the environment and ecological security. The present paper proposes a novel method for one-step producing potassium-containing fertilizer synergistically extracting Al 2 O 3 by KOH hydrothermally treating red mud or CFA. In this paper, the dissolving ratio of Al 2 O 3 in the K 2 O-Al 2 O 3 -H 2 O ternary system and the extraction of Al 2 O 3 from red mud or CFA after hydrothermal treatment with KOH were investigated. The phase structure transformation of leaching residue obtained under various conditions was analyzed by X-ray diffraction and scanning electron microscopy, and the fertilization efficiency of the products was verified by potting experiments. The results show that the dissolving ratio of Al 2 O 3 can reach the highest value of 85.04% at 120 °C with the K 2 O mass fraction of 24.90% in the ternary system. When red mud or CFA was hydrothermally leached with 240 g/L K 2 O at 240 ℃, the Al 2 O 3 extraction rates of 25.50% and 31.42% could be separately obtained, and the leachate could be reused. The main phases of the leaching residue were kaliophilite, illite, and megakalsilite, and the content of K 2 O was 7.83% and 26.89%, which can be applied as potassium-containing fertilizer to improve soil fertility and effectively promote the growth of pakchoi. The process improves the comprehensive utilization of red mud and CFA without secondary pollution, reduces the negative impact on the environment, and opens up a new way to apply bulk solid waste in the agricultural field. [ABSTRACT FROM AUTHOR]

Soil testing is the foundation of fertilizer recommendations in the United States. Fertilizer recommendations have primarily been developed by land‐grant universities with limited coordination among programs. The individual state approach to develop fertilizer recommendations has resulted in discrepancies in recommended soil sampling protocols, soil analysis methods, and fertilizer recommendations at similar soil nutrient levels. A national survey was developed to summarize the status of soil testing and fertility work in the United States to inform future collaborative efforts among states and regions and identify opportunities to harmonize recommendation guidelines. Topics included relevant funding, multi‐state collaborations, state soil‐test recommendations and related data, fertilization philosophies, and analytical and soil sampling methods. Responses from 48 states and Puerto Rico showed inconsistencies across state boundaries in every category. The number of faculty full‐time equivalents working in soil fertility now averages 1.3 per state, a 21.5% decrease every 10 years since the 1950s. Land‐grant university soil‐test‐based phosphorus (P) and potassium (K) recommendation philosophies were categorized as Sufficiency (37%), Build and Maintain (19%), hybrid (20%), or multiple philosophies for which recommendations are provided (20%). Respondents in two states did not know the recommendation philosophy (4%). Fertilizer‐P and K recommendations for corn (Zea mays L.) were based on eight different extractants with differences across and within regions. While there have been some successful regional efforts in the past, additional multi‐state collaborative efforts are needed to identify research gaps and develop comprehensive strategies to update soil‐test correlation and calibration data to address modern agronomic, economic, and environmental concerns. Core Ideas: A national survey determined the status of soil fertility recommendations in the United States.This paper focuses on survey results regarding P and K fertilizer recommendations.Soil fertility evaluation methodology, interpretations, and recommendations lack consistency among states.41% of states do not know when their P and K correlations were established or last validated.Multi‐state collaboration and funding for soil fertility research are needed to improve P and K recommendations. [ABSTRACT FROM AUTHOR]

The paper analyzes the positive and negative aspects of various technological solutions for the liquid brines used during the development of polymineral potash ore deposits and considers the problem of determining the choice of the optimal approach by considering geological, technical, environmental, and financial factors. The study of the issues of utilization and reduction of the liquid brines components of discharges in the production of potash fertilizers, the simultaneous reduction of valuable components loss with liquid discharges, and, due to this, increasing the production of potash fertilizers, and the usage in the technology of mine brines, are an urgent and important scientific and engineering challenge of the potash industry. Technologically, several alternative solutions can reduce the number of liquid by-products placed in sludge storage. The work used analytical methods, including statistical data processing, modeling, pre-design studies of technological solutions, and assessment of economic costs. Excess brines of potash mining and processing plants are liquid waste obtained during the production of potash fertilizers – MOP и SOP. The accumulation of excess brines in sludge storage facilities is estimated at millions of cubic meters per year. However, the expansion of the sludge storage facilities area and the construction of dams are only temporary solutions. They are associated with risks in the design, construction, and operation of hydraulic structures, increasing the risks of brine leakage into open and underground water basins. Therefore, it makes it necessary to use other methods of brine disposal. Depending on the nature of the processed polymineral potash ores, several methods can be combined to dispose of excess brines at once: backfilling, osmosis, injection into deep horizons, and multistage evaporation. The most optimal combination of brine reduction technologies for potassium-magnesium processing plant's raw materials is the following: 60% is disposed of by usage of vacuum evaporation units, 20 % by injecting excessive brines into deep absorbing horizons, and 10%—20% should be used for backfilling or additional products production. [ABSTRACT FROM AUTHOR]

The period of cultivation of large-diameter timber stands is affected by the relatively slow initial growth of Picea species. The combination of fertilization and nurturing measures can promote the growth of tree height and ground diameter. In this paper, 12 fixed plots of 10m×10m were randomly set up in a larch understory with 10 a juvenile Picea koraiensis plantations as the study subjects. Fertilizer types were selected as N (N - urea), NP (NP - urea+superphosphate), NPK (NPK - urea+superphosphate+potassium phosphate). Two types of fertilization time were set: (1) pre-middle-late growing seasons fertilization: fertilizer was applied per year at the beginning (mid-May), middle (mid-July), and late (mid-August) of the growing season, with fertilization repeated for four consecutive years. (2) Pre-middle-end growing seasons fertilization: fertilizer was applied per year at the beginning ( mid - May), middle (mid-July) and end (mid-September) of the growing season, with fertilization repeated for four consecutive years. Light-felling was set as follows, after one growing season of fertilization, accretion cutting the upper larch trees, and the stand density was 0. 6 after tending. By studying the effects of fertilization and light-felling on the growth of trees, the aim was to develop fertilization management techniques to promote the growth of juvenile P. koraiensis, so as to shorten the growth cycle of young plantation. The effect of applying NPK fertilizer on promoting the height and diameter growth of juvenile P. koraiensis was better than applying only a single fertilizer or a mixture of nitrogen and phosphorus fertilizers. The annual tree height and ground diameter growth were 41.11 % and 49.81 % higher in the treatments NPK fertilizer applied pre-mid-end growing seasons than those treated with NPK in the premid-late growing seasons. After light-felling, the annual growth of tree height between different years was not significantly different, but that of the ground diameter was significantly different. The annual growth of tree height and ground diameter after three growing seasons were not significantly different from that before light-felling. By combining fertilizer application in the pre-middle-late growing seasons with light-felling treatments, the annual growth of tree height and ground diameter were significantly different from the control group after two growing seasons, only the annual growth of ground diameter was significantly different from the control group after three growing seasons. After three growing seasons of nitrogen, phosphorus and potassium fertilizers (NPK2) combined with light-felling in the pre-mid-end of growing seasons, the annual growth of ground diameter was 153.16 % and 10.31 % higher than that of the control and pre-middle-late of growing seasons NPK fertilizers (NPK1) combined with light-felling. The combination of fertilization and light-felling treatments can increase the annual growth of P. koraiensis ground diameters, reaching a significant level at four consecutive years of fertilization. Fertilizer application at the pre-mid-end stages of the growing season is more effective than at pre-mid-late stages. The research provides a basis for solving the problem of slow growth of P. koraiensis plantation at a young age and shortening the cultivation period of large-diameter timber plantation of P. koraiensis. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to investigate the effects of balanced fertilization on the fertility and microbial community structure of Amaranthus tricolor L. inter-root soil, to provide a reference basis for shaping a fertile A. tricolor inter-root soil microenvironment and constructing a high-yielding and high-quality A. tricolor production technology system.【Method】Based on traditional and high-throughput sequencing techniques, the study analyzed the changes of soil fertility and microbial community structure in the inter-rhizosphere of A. tricolor under the conditions of blank control(CK),potassium deficiency fertilization(NP),nitrogen deficiency fertilization(PK),phosphorus deficiency fertilization(NK) and balanced fertilization[188.0,53.0 and 50.0 kg/hm² of nitrogen, phosphorus and potassium(NPK) fertilization, respectively].【Result】Application of different ratios of N,P and K fertilizers increased β-glucosidase, aminopeptidase and phosphatase activities in A. tricolor inter-root soil; Compared with the NPK treatment, the microbial biomass carbon(C),N and P contents of A. tricolor inter-root soil were generally lower in the non-balanced fertilizer treatment; All fertilizer treatments contributed to increase the bacterial diversity and richness of A. tricolor inter-root soil, but only the balanced fertilizer treatment increased the diversity and richness of fungi in the inter-root soil of A. tricolor. At the level of bacterial phylum classification, abundance percentage of the dominant bacterial phylum Proteobacteria, Acidobacteriota, Patescibacteria, Gemmatimonadota, Bacteroidota and Myxococcota in A. tricolor inter-rhizosphere soil in all fertilizer treatments increased, but that of Actinobacteriota and Chloroflexi decreased. At the taxonomic level of bacterial genera, fertilization not only obviously changed the abundance of bacterial genera at the taxonomic level of A. tricolor roots, but also enriched some specific dominant bacterial genera(unclassified＿o＿ Saccharimonadales,norank＿ f＿LWQ8 and Sphingomonas). At the fungal phylum taxonomic level, Ascomycota, Chytridiomycota, Mortierellomycota and unclassified＿ k＿ Fungi were the dominant fungi common to all fertilizer treatments; At the taxonomic level of fungal genera, Plectosphaerella,unclassified＿ f＿ Chytridiaceae,Gibellulopsis,Phialemonium,Mortierella,unclassified＿ k＿ Fungi and Myrothecium were the dominant fungal genera in the top 10 in terms of abundance in the different fertilizer treatments and missing from CK.【Conclusion】The application of different ratios of N,P and K fertilizers helped to improve the fertility of A. tricolor inter-roots soil and create a healthy soil environment, among which the balanced application(188.0,53.0 and 50.0 kg/hm2 of N,P and K fertilizers respectively) was the most effective in increasing the abundance and diversity of A. tricolor inter-root soil bacteria and fungi and improving the microenvironment of A. tricolor inter-root soil. It can be applied in the production of A. tricolor. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to study the effect of physicochemical properties of rhizosphere soil on quality of Coptis deltoidea C. Y. Cheng et Hsiao and further to provide scientific basis for ecological planting of C. deltoidea. [Method] Eighteen soil physicochemical indexes and six alkaloids of C. deltoidea were determined by soil agrochemical analysis and high performance liquid chromatography (HPLC) . Meanwhile, correlation analysis and redundancy analysis were used to reveal the relationship between physico-chemical properties of soil and the accumulation of alkaloids in C. deltoidea. [Result] The total contents of 6 alkaloids in taproots of C. deltoidea that grew for two to five years old were 3. 716%, 5. 720%, 8. 552% and 8. 866%, respectively, and the contents of berberine were 1. 779%, 3. 620%, 5. 469% and 5. 706%, respectively, which indicated that the four-year-old C. deltoidea had met the harvesting standard. The correlation analysis of alkaloids and soil factors in the taproot of C. deltoidea showed that total amount of 6 alkaloids and berberine content were significantly positively correlated with available potassium (P＜0. 05), and significantly negatively correlated with nitrate nitrogen and sodium (P＜0. 01) . And a significant negative correlation was also seen between sodium and rhizobine (P＜0. 01) . There was significant negative correlation between coptidine and copper (P＜0. 05), and extremely significant negative correlation between coptidine and sodium (P ＜0. 01) . Finally, according to the redundancy analysis of alkaloids in taproot and soil factors, the contents of available phosphorus, available potassium and sodium in soil were the dominant factors affecting the accumulation of alkaloids in C. deltoidea, while ammonium nitrogen and pH were the more important factors. [Conclusion] In the process of planting C. deltoidea, high-quality soil environmental conditions can be selected from the planting source, that is, the soil with high nitrogen and potassium, low phosphorus and sodium and acidic pH can be selected. Moreover, the alkaloid content of C. deltoidea can be regulated by adding potassium fertilizer and nitrogen fertilizer, controlling the application amount of phosphate fertilizer and reducing the content of sodium in the soil. [ABSTRACT FROM AUTHOR]

Globally, there is growing interest to recycle organic waste using insect larvae into high-quality frass fertilizer through circular economy approach. This paper presents the first comparative report on the nutrient concentrations, fertilizing indices, nutrient supply potentials and compost maturity of nine edible insect frass fertilizers. Our results revealed that frass fertilizers from all the insect species had adequate concentrations and contents of macronutrients [nitrogen (N), phosphorus (P), potassium (K)], secondary nutrients (calcium, magnesium, and sulphur) and micro-nutrients (manganese, copper, iron, zinc, boron, and sodium). The fertilizing indices of the frass fertilizers were above 3. However, black soldier fly (BSF) frass fertilizer had significantly higher N (20–130%) and K (17–193%) concentrations compared to others. The P concentration of Gryllus bimaculatus frass fertilizer was 3–800% higher compared to those of frass fertilizers from other insect species. The potential N and K supply capacities of BSF frass fertilizer was 19–78% and 16–190% higher, respectively. The P supply capacity of cricket frass fertilizer was 17–802% higher compared to others. The highest seed gemination rate (> 90%) and germination index (267%) were observed in seeds treated with BSF frass fertilizer. Frass fertilizer obtained from the other eight insect species showed medium to high phytotoxicity. These findings demonstrate that insect frass fertilizers are promising alternatives to existing commercial fertilizers (i.e., mineral, and organic) for improved soil health and crop yield. [ABSTRACT FROM AUTHOR]

The role of nitrite (NO2−) and nitrate (NO3−) is essential in the global nitrogen cycle. Monitoring their concentration in environmental and industrial aqueous samples, surface water, soil, food and agricultural products are of high importance. Especially, the effect of anthropogenic emission, i.e., intensified agriculture is essential due to the overuse of nitrogen, phosphorus and potassium fertilizers. The most widely utilized methods for nitrate and nitrite determination are colorimetry, potentiometry, UV absorption and liquid chromatography. Among them, UV spectroscopy is the most frequently used technique due to the fact of its versatility and simplicity. However, there are industrial and academic needs to develop new methods to overcome some drawbacks of the currently used techniques such as an inadequate limit of detection and potential interferences with organic compounds in the sample. In this paper, we report on the development of a new analytical method based on capillary electrophoresis separation with high-sensitivity UV detection, capable of measuring trace concentrations of nitrite and nitrate well below the current limits of UV spectroscopy methods. During the development process special attention was paid to practical aspects, i.e., the method was tested to quantify nitrate and nitrite in various surface water samples. [ABSTRACT FROM AUTHOR]

Ageratina adenophora originating from central America has flooded forests, pastures, and farmland in more than 40 tropical and subtropical countries, causing huge ecological disasters and economic losses. In this paper, we intended to use a complex inoculum composed of Pseudomonas putita and Clostridium thermocellum to in-situ compost A. adenophora debris and then to compare the phytotoxicity of extracts from uncomposted and composted A. adenophora (UCA and CA respectively) to barley seed germination and young seedling growth. A field experiment was finally conducted to reveal the effects of UCA and CA on barley nutrients uptake, yield, grain quality, soil enzyme activities, microbial biomass and biodiversity. In-situ composting sharply decreased 4,7-dimethyl-1-(propan-2-ylidene)-1,4,4a,8a-tetrahydronaphthalene- 2,6(1H,7H)-dione(DTD) and 6-hydroxy-5-isopropyl-3,8-dimethyl-4a,5,6,7,8,8a-hexahydronaphthal en-2(1 H)-one(HHO) from 2096.3 and 743.7 mg kg-1 in uncomposted A. adenophora to 194.4 and 68.19 mg kg-1 in composted A. adenophora. UCAE showed negative influences on seed germination performances (except lower rates on germination percentage). The mechanism may be the inhibition of bio-macromolecules hydrolysis (including proteins, starch, and phytin) in endosperms and their hydrolysates for forming new plants. CAE promoted seed germination and seedling growth, increased chlorophyll levels in leaves, and stimulated dehydrogenase and nitrate reductase activities in plants, while UCAE got opposite performance. Compared with chemical fertilizers, application of CA in combination with chemical fertilizers significantly improved plant nutrient uptake (nitrogen, phosphorus, and potassium), yield, grain quality, quantity of 16S rDNA sequences, richness and diversity of bacterial communities in contrast to UCA which behaved otherwise. Taken together, the use of the microbial agent to in-situ compost A. adenophora may be an effective approach for agricultural use of A. adenophora debris as a plant-friendly organic fertilizer, being undoubtedly worth advocating. [ABSTRACT FROM AUTHOR]

Research was carried out in Giulvăz, Timiş County, in 2018-2020, in a plantation located on a preluvosol. The plantation was established in the autumn of 2017 and has a total area of 3.5 ha: 2 ha with apple, 1 ha with plum and 0.5 ha with a mixture of various species. As fertilizers, 30 t/ha manure was applied in the autumn of 2017, before the plantation was set up. Results show different contents of nitrogen, phosphorus and potassium, depending on the vegetation period of the trees: in April, the content is higher compared to September due to consumption of nutrients of the trees during vegetation, a normal consumption because, during this period, the trees need the application of fertilizers in order to be able to fructify. In this respect, research was carried out by the authors of this paper and by other researchers in the field, but concrete results in this respect can only be observed after a number of years since nitrogen, phosphorus and potassium content in the soil is changing continuously as a result of consumption by trees. In Romania, research in this such a complex area is quite limited because of both the rather high cost of organic fertilizers and of the general lack of financial resources necessary to continue research and present results. This paper is original, both in terms of the information it supplies to those interested in the fertility of soils cultivated with trees, as well as in terms of the practical solutions it provides in two important areas: soil science and fruit growing. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed order to explore the improvement effects of compound microbial fertilizer on soil nutrient content, a field test of applying compound microbial fertilizer combined with farm manure on soil restoration in karst area was carried out at the test site of Hylocereus polyrhizus（pitaya） orchard in Guohua town, Pingguo city, Guangxi.【Method】Nine fertilization treatments（T1-T9） were set up in the pitaya orchard. The soil nutrient content, microbial quantity and soil enzyme activity of each treatment were, with no fertilization and no compound microbial fertilizer as control（CK）. The effects on soil biological characteristics and soil fertility were discussed.【Result】The mixed application of compound microbial fertilizer and farm manure were able to improve the contents of soil organic matter（SOM）,total nitrogen（TN）,total phosphorus（TP）,total potassium（TK）,available nitrogen（AN）,available phosphorus（AP） and available potassium（AK）,and promote the increase of soil bacteria, actinomycetes, nitrogen-fixing bacteria and yeast, and also inhibit the growth of harmful microorganisms and fungi. The activities of soil urease, sucrase, catalase, polyphenol oxidase and acid phosphatase were enhanced. The T9 treatment provided the best improvement, as compared with CK,the contents of SOM, TN,TP,TK,AN,AP and AK increased by 65%,31%,83%,37%,62%,47% and 31%. The number of bacteria, actinomycetes, azotobacter and yeasts increased by 22%,86%,63% and 84%,while the number of fungi decreased by 49%.The activities of urease, sucrase, catalase, polyphenol oxidase and acid phosphatase increased by 51%,60%,162%,55% and 83%,respectively.【Conclusion】Applying compound microbial fertilizer with farm manure in the pitaya orchard in rocky desertification area can improve soil fertility by increasing the content of soil nutrient, increasing the number of soil bacteria, actinomycetes, nitrogen-fixing bacteria, yeasts, inhibiting the increase of fungi, and enhancing soil enzyme activity. Especially, the effect of 2.50 kg/plant farmyard manure+3.00 kg/plant compound microbial fertilizer is the best. [ABSTRACT FROM AUTHOR]

This paper studied the index system of ecological balanced fertilization for maize by data mining method based on data of "3414 fertilizer field trials" of maize by published papers from national soil testing and recommendation since 2005. The results and conclusions were as follows. CD Soil nutrient content could not be used as indicator of fertilizer application of maize. @The conceptual model of N conversion rate of maize for plot was YΝ = a + b X optimum production - c X optimum fertilizer amount of N - d X optimum phosphorus application amount - e X optimum potassium application amount - f x temperature in growth season - g x rainfall in growth season. The conceptual model of P conversion rate of maize for plot was YΚ = a + b x optimum phosphorus application amount - c X optimum nitrogen application amount - d X optimum potassium application amount. The conceptual model of K conversion rate of maize for plot was YΚ = a + b x optimum yield - c x optimum nitrogen application amount - d x optimum phosphorus application amount - e X optimum potassium application amount - f X temperature in growth season - g X rainfall in growth season. @ The conceptual model of the optimum fertilizer amount of N of maize for plot was YΝ = a+ bx optimum phosphorus application amount + c x optimum potassium application amount + d x temperature in growing season + e X rainfall in growing season, and the conceptual model of the optimum fertilizer amount of P was YΡ = a + b X optimum nitrogen application amount, and the conceptual model of the optimum fertilizer amount of K was YΚ = a+ b x optimum nitrogen application amount + c x temperature in growth season + d x rainfall in growth season - e x optimum yield. @ The conceptual model of relative abundance - deficiency value of soil N of maize for plot was that YΝ = a, and the conceptual model of relative abundance - deficiency value of soil P was YΡ = a, and the conceptual model of relative abundance - deficiency value of soil K was Yκ = a + b x optimum nitrogen application amount + c x optimum phosphorus application amount. [ABSTRACT FROM AUTHOR]

This paper studied the relationships between utilization ratios and conversion rates of nitrogen, phosphorus and potassium for wheat by data mining method based on data of "3414 fertilizer field trials" of wheat by published papers from national soil testing and recommendation since 2005. The results and conclusions were as follows; Q) the conceptual model of fertilizer utilization ratio of wheat for plot was that, YN = a + b x optimum nitrogen application amount + c X optimum fertilizer amount of K + d X rainfall in growth season, YP = a + b X optimum fertilizer amount of K + c X rainfall in growth season, Yk = a + b X temperature in growth season + c X rainfall in growth season - d X optimum yield - e X optimum nitrogen application amount, respectively. @ Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships. No significant relationships: 13, of which 8 were soil nutrients, the results showed that soil nutrients had little effect on nutrient conversion rate and fertilizer utilization ratio; consistent significant relationships; 4, they were all nitrogen and phosphorus, explaining the importance of nitrogen and phosphorus; contrary significant relationships: 6, they were all nitrogen and phosphorus, illustrating that phosphorus and nitrogen had inhibitory effect; complementary significant relationships; 31, the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season, while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons. It showed that the fertilizer utilization rate was significantly correlated, or the nutrient conversion rate was significantly correlated. [ABSTRACT FROM AUTHOR]

This paper studied the nitrogen index system of ecological balanced fertilization for rice by data mining method based on data of" 3414 fertilizer field trials" of rice by published papers from national soil testing and recommendation since 2005. The results and conclusions were as follows. (D Soil nutrient content could not be used as fertilization indicator of rice. @The conceptual model of nitrogen conversion rate of rice for plot was YN =a+ b X optimum production - c X optimum nitrogen fertilization amount - d X optimum phosphorus fertilization amount, and the conceptual model of phosphorus conversion rate was Yp =a - bx optimum phosphorus fertilization amount - c x optimum potassium fertilization amount, and the conceptual model of potassium conversion rate was YK =a+ b X optimum production+ c X optimum nitrogen fertilization amount - d X optimum potassium fertilization amount - e x annual average precipitation. @ The conceptual model of the optimum nitrogen fertilization amount of rice for plot was YN =a + b x optimum production +c Xoptimum phosphorus fertilization amount -d X annual average precipitation, and the conceptual model of the optimum phosphorus fertilization amount was YP =a + b x optimum nitrogen fertilization amount + c x optimum potassium fertilization amount, and the conceptual model of the optimum potassium fertilization amount was YK =a + b X optimum phosphorus fertilization amount + c X annual average precipitation. @The conceptual model of relative abundance - deficiency value of soil nitrogen of rice for plot was YN =a - b x optimum nitrogen fertilization amount - c x optimum potassium fertilization amount, and the conceptual model of relative abundance - deficiency value of soil phosphorus was Yp =a + b x soil available potassium - c x optimum potassium fertilization amount, and the conceptual model of relative abundance - deficiency value of soil potassium of rice was YK =a - b X optimum potassium fertilization amount. [ABSTRACT FROM AUTHOR]

Globally, there is growing interest to recycle organic waste using insect larvae into high-quality frass fertilizer through circular economy approach. This paper presents the first comparative report on the nutrient concentrations, fertilizing indices, nutrient supply potentials and compost maturity of nine edible insect frass fertilizers. Our results revealed that frass fertilizers from all the insect species had adequate concentrations and contents of macronutrients [nitrogen (N), phosphorus (P), potassium (K)], secondary nutrients (calcium, magnesium, and sulphur) and micro-nutrients (manganese, copper, iron, zinc, boron, and sodium). The fertilizing indices of the frass fertilizers were above 3. However, black soldier fly (BSF) frass fertilizer had significantly higher N (20–130%) and K (17–193%) concentrations compared to others. The P concentration of Gryllus bimaculatus frass fertilizer was 3–800% higher compared to those of frass fertilizers from other insect species. The potential N and K supply capacities of BSF frass fertilizer was 19–78% and 16–190% higher, respectively. The P supply capacity of cricket frass fertilizer was 17–802% higher compared to others. The highest seed gemination rate (> 90%) and germination index (267%) were observed in seeds treated with BSF frass fertilizer. Frass fertilizer obtained from the other eight insect species showed medium to high phytotoxicity. These findings demonstrate that insect frass fertilizers are promising alternatives to existing commercial fertilizers (i.e., mineral, and organic) for improved soil health and crop yield. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to the problems of shallow soil arable layer depth, soil salinization and reducing maize yield in maize fields in Ningxia Yinbei irrigation area, the effe cts of different Fenlong tillage depths on soil available nutrients and maize yield were studied to select suitable Ningxia silver the Fenlong tillage technology in the north yellow irrigation area realizes the benign production of the soil. [Method] This experiment adopted a randomized block design, with Fenlong tillage depth 40 cm ( FIAO: Tillage depth 0 - 40 cm), Fenlong tillage depth 50 cm ( FISO: Tillage depth 0 - 60 cm) and traditional rotary tillage ( CK: Tillage depth 0 - 20 cm) as a control. Soil samples were collected at different growth stages of maize to determine soil water content, pH, available nitrogen, available phosphorus, available potassium and organic matter content and maize yield under different F enlong tillage treatments variety. [ Result] The soil water content of different Fenlong tillage treatments was significantly different in different growth periods of maize compared with traditional tillage. From the emergence period to the milking period, FIAO was significantly higher than that of CK, and the highest soil water content of FIAO was 16. 99%, followed by FISO, the soil water content was 16. 86%, which was 6. 5% and 5. 8% higher than that of CK, respectively; FIAO and FISO could significantly reduce the soil pH; FIAO and FISO in the maize jointing and tasseling period had significantly higher soil available nitrogen content than that of CK, espec ially FIAO, the soil available nitrogen content increased significantly after Fenlong tillage treatment; The average content of soil available phosphorus in FIAO and Fl.SO during the entire growth period was higher than that of CK, especially Fl.SO was the most significant after Fenlong tillage treatment, and t he content of soil available phosphorus was also significantly increased after Fenlong tillage treatment ; FIAO had significantly higher soil available potassium content t han that of CK in the early period of maize growth, FIAO could effectively increase the soil available potassium content; FIAO and Fl.SO had significant soil organic matter content in both the emergence period and jointing and tasseling period higher than that of CK, and the soil organic matter content after Fenlong tillage treatment significantly increased; Among the yield components of maize kernels, FIAO and Fl.SO had a greater effects on the hundred-kernel weight, number of kernels per ear, number of ears per 6fJ7 m2 and yield of maize kernels CK increased significantly, with FIAO being the most significant, which increased by 48. 22 % compared with traditional tillage. The yield of maize was significantly positively correlated with the content of available nitrogen and available potassium in t he soil. [Conclusion] Fenlong tillage can effectively reduce soil pH and increase soil water content, thereby increasing soil available nutrient and organic matter content, also, the content of available nitrogen and available potassium in the soil are the main factors affecting maize yield and ultimately increase maize yield. Therefore, it is believed that Fenlong tillage can be used as a new agronomic measure for the saline l and of N ingxia Yinbei irrigation area. [ABSTRACT FROM AUTHOR]

【Objective】In order to provide a theoretical basis for the increase of yield and output value of tea and the nutrient absorption of big-leaf tea species in modern tea garden,this paper studied the effects of optimized fertilization technology on the quality of tea in modern tea garden of Pu’er.【Method】In this paper,‘Yunkang14’,an excellent tea variety,was used as the test material,and the plot experiment was carried out with treatment 1(no fertilization,CK),treatment 2(conventional fertilization),and treatment 3(Formula fertilization) and treatment 4(Optimized formula fertilization).The treatment 3 and treatment 4 had the same amount of fertilizer applied,but different fertilization methods.【Result】The accumulation of nitrogen,phosphorus and potassium in the new shoots of tea tree in treatment 4 were significantly higher than those in other treatments.The contents of phosphorus and potassium in tea shoots were significantly higher than other treatments; the agronomic efficiency of treatment 4 was 9.58 kg/kg for nitrogen fertilizer,22.99 kg/kg for phosphate fertilizer and 28.74 kg/kg for potash fertilizer,respectively,and their partial productivity was 23.14,55.54 and 69.42 kg/kg respectively.Compared with treatment 2 and treatment 3,the 100-bud weight of treatment 4 increased by 12.74 % and 2.06 %,the germination density increased by 10.84 % and 1.14 %,the fresh leaf yield increased by 15.71 % and 3.98 %,and the output value increased by 28 135 and 3224 yuan/hm2,respectively.【Conclusion】In the field experiment,the optimized fertilization technology can significantly improve the tea yield,output value and nutrient uptake of Pu’er modern tea garden.It is suggested to promote the optimized fertilization technology in Pu’er modern tea garden tea production [ABSTRACT FROM AUTHOR]

The accident occurring at the Fukushima Daiichi nuclear power plant on March 11, 2011 resulted in leakage of a large amount of radionuclides, contaminating farmlands, including rice field, in Fukushima and its neighboring prefectures. Potential contamination of the rice growing these areas by the radionuclides has thus attracted public attention. The objective of this paper is to analyze rice contamination in this region and its remediation. Literature review showed that the radionuclide that was most potential to contaminate the rice is the radioactive cesium. Among all available methods to detect radioactive cesium in rice grain, belt conveyor testers is quicker in measurement but is less accurate, while germanium semiconductor detectors is more accurate but is tedious. Rice contamination by cesium accumulation is modulated by a multitude of factors, one of which is fertilization. For example, potassium fertilizer (potassium chloride is more effective than potassium metasilicate) can reduce the absorption of the radioactive cesium in rice, while nitrogen fertilizer works in the opposite. The movement and transfer of radioactive cesium in soil was affected by its concentration, potassium content, immobilization of the cesium by soil, and the thickness of the topsoil. Apart from these, rice cultivars also affect cesium accumulation. Different methods for ameliorating rice contamination by radionuclides had been developed and tested. In paddy fields, rice contamination by cesium can be reduced by amending the soil or planting. The radioactive cesium is sportive to soil and cyanobacteria can be used to facilitate the exfoliation of top soil. Also, rice is a shallow-rooted plant and deep ploughing could bury the contaminated topsoil beyond the reach of roots so as to reduce its uptake by rice. Secondary contamination can be avoided by controlling fertilization and irrigation, and the transformation of the radioactive cesium from soil to rice can be inhibited by amending the soil with schwertmannite, zeolite and vermiculite, or by controlling fertilizer application rate and the secondary contamination. Implementation of above mitigating methods over the past few years reduced the radioactive cesium content in rice in Fukushima Prefecture to 25 Bq/kg in 2014 (the radiation level set by the Food Sanitation Act of Japan in 2012 was 100 Bq/kg). This paper has implications for constructing a database for mitigating and remediating crop contamination by radionuclides which is also relevant to food production in China. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to study the effect of urea-formaldehyde slow-release fertilizer rods on the growth and nutrient absorption of rubber seedlings, and provide a theoretical basis for the application of urea-formaldehyde slow-release fertilizer rods on rubber trees. [Method] Using urea-formaldehyde slow-release fertilizer with 0%,25%, 50%, and 75 % of total nitrogen as the test fertilizer, the pot experiment of rubber tree seedlings was carried out to study the effects of different urea-formaldehyde slow-release fertilizer rods on the growth and nutrient absorption of rubber tree seedlings. [ Result] When the urea-formaldehyde slow-release fertilizer rod with 50% urea-formaldehyde nitrogen was applied, the plant height and stem diameter of the rubber seedlings were the largest, which were 149. 32 cm and 17. 96 mm,respectively. But it was not significantly different from conventional fertilizer treatment. With the increase of the proportion of urea-formaldehyde nitrogen, the whole plant biomass, nitrogen absorption, phosphorus absorption, potassium absorption and fertilizer use efficiency of the rubber tree seedlings all showed as increased first and then decreased. When the urea-formaldehyde slow-release fertilizer rod with 50 % urea-formaldehyde nitrogen was applied, the whole plant biomass, nitrogen absorption, phosphorus absorption,potassium absorption and fertilizer use efficiency of the rubber tree seedlings were the largest. [Conclusion] It is most beneficial to the growth of rubber seedlings and nutrient absorption of rubber tree seedlings when the urea-formaldehyde slow-release fertilizer rod with 50% urea-formaldehyde nitrogen. [ABSTRACT FROM AUTHOR]

[Objective] In order to explore the effects of low nitrogen stress on the growth and soil nutrients of tartary buckwheat in the hilly and gully regions of the Loess Plateau, the present paper determined plants and soil characteristics of tartary buckwheat with different nitrogen stress among the whole growth period It could provide a scientific basis for the optimal management of farmland nitrogen fertilizer in the loess hilly and gully region. [Method] The study took different nitrogen buckwheat (Heifeng No. 1, HF, intolerant to low nitrogen, Diqing Tartary Buckwheat, D Q, tolerant to low nitrogen) as the research objects, and set 3 levels of nitrogen application as follows : 0 kg/hm² (NO, no nitrogen treatment), 80 kg/hm² (Nl, low-nitrogen treatment), 160 kg/hm² (N², normal nitrogen treatment). Plant indexes (plant height, stem thickness, leaf area) and soil characteristics (soil water content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus, total potassium) were determined during the whole growth periods. [Result] (i) Cultivar, nitrogen treatment and the interaction between the two had extremely significant effects on tartary buckwheat plants (P < 0. 01). Under Nl treatment, the plant height, stem thickness and leaf area of DQ in the seedling stage were 9. 7 %, 10. 5 %, and 17. 7 % higher than that of HF. The plant height and stem thickness of DQ in the flowering stage were 9. 5 % and 7. 4 % higher than that of HF. The stem thickness and leaf area of DQ were 5. 4 % and 3 6. 2 % higher than those of HF. (ii) The cultivars, nitrogen treatments and the interaction between the two had a significant impact on soil nutrients (P < 0. 01). After the growth period, the soil nutrient indexes of the two cultivars were lower than those of the sowing period, but soil organic matter, available nitrogen, available phosphorus, available potassium, total nitrogen, and total potassium of DQ were higher than those of HF under Nl treatment of98. 8%, 11. 6%, 44. 7%, 11. 6%, 80. 41%, 4. 2%, respectively. [Conclusion] The DQ (low nitrogen tolerant) has better water conservation and green manure benefits than HF (intolerant to low nitrogen) as its larger leaf area and stem thickness could buffer the direct erosion of rainfall on the ground and resist wind to prevent plant lodging. In addition, the rhizosphere soil nutrient content of DQ was higher than HF after being harvested which could reduce the fertilizer consumption in the next season and was also more conducive to the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

[Objective] In order to explore the effects of low nitrogen stress on the growth and soil nutrients of tartary buckwheat in the hilly and gully regions of the Loess Plateau, the present paper determined plants and soil characteristics of tartary buckwheat with different nitrogen stress among the whole growth period It could provide a scientific basis for the optimal management of farmland nitrogen fertilizer in the loess hilly and gully region. [Method] The study took different nitrogen buckwheat (Heifeng No. 1, HF, intolerant to low nitrogen, Diqing Tartary Buckwheat, D Q, tolerant to low nitrogen) as the research objects, and set 3 levels of nitrogen application as follows : 0 kg/hm² (NO, no nitrogen treatment), 80 kg/hm² (Nl, low-nitrogen treatment), 160 kg/hm² (N², normal nitrogen treatment). Plant indexes (plant height, stem thickness, leaf area) and soil characteristics (soil water content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus, total potassium) were determined during the whole growth periods. [Result] (i) Cultivar, nitrogen treatment and the interaction between the two had extremely significant effects on tartary buckwheat plants (P < 0. 01 ). Under Nl treatment, the plant height, stem thickness and leaf area of DQ in the seedling stage were 9. 7 %, 10. 5 %, and 17. 7 % higher than that of HF. The plant height and stem thickness of DQ in the flowering stage were 9. 5 % and 7. 4 % higher than that of HF. The stem thickness and leaf area of DQ were 5. 4 % and 3 6. 2 % higher than those of HF. (ii) The cultivars, nitrogen treatments and the interaction between the two had a significant impact on soil nutrients (P < 0. 01). After the growth period, the soil nutrient indexes of the two cultivars were lower than those of the sowing period, but soil organic matter, available nitrogen, available phosphorus, available potassium, total nitrogen, and total potassium of DQ were higher than those of HF under Nl treatment of98. 8%, 11. 6%, 44. 7%, 11. 6%, 80. 41%, 4. 2%, respectively. [Conclusion] The DQ (low nitrogen tolerant) has better water conservation and green manure benefits than HF (intolerant to low nitrogen) as its larger leaf area and stem thickness could buffer the direct erosion of rainfall on the ground and resist wind to prevent plant lodging. In addition, the rhizosphere soil nutrient content of DQ was higher than HF after being harvested which could reduce the fertilizer consumption in the next season and was also more conducive to the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to study the optimum fertilizer on tobacco cultivation, which would provide a theoretical basis for the reasonable fertilizer application of tobacco leaves in Liangshanyi autonomous prefecture. [Method] Taken Yunyan 87 as tested materi als, the effect of different fertilizer ratios of nitrogen ( N), phosphorus ( P) and potassium ( K) on the leaf biomass, quality components and Cd accumulation of Nicotiana tabacum were studied by pot assay. [ Result]The fertilizer application could not only promote the growth of to bacco and increase the leaf biomass, but also had a positive effect on the accumulation of quality components and the coordination of qnalitative proportion. The contribution efficiency of nitrogen, phosphorus and potassium to plant height and leaf biomass of tobacco was N > P > K. Potassium fertilizer played an important role in the accumulation of potassium in tobacco leaves. The contents of nicotine and total nitrogen were significantly increased, and the coordinated proportion of qnality components was presented under the high level of nitrogen fertilizer. Cd content was an important index to evaluate the qnality and safety of tobacco leaves. The content of Cd in tobacco leaves was in the order of lower leaves > middle leaves > upper leaves. Meanwhile, the abilities of Cd absorption and accumulation of tobacco plants to soil were sig nificantly improved with the high level of combined nitrogen and phosphorus fertilizer, nd storage in tobacco leaves, however, there was no notable influence for potassium fertilizer. [ Conclusion] In summary, the best fertilizer recommended by this pot assay was the treatment of N212K2,when the ration ofN: p: K was 1:0.45:2. 06, average plant height and leaf biomass were 79. 2 cm and 55. 2 g; With 3. 22%,3. 05%,3. 76%,25. 89% and 27. 74% for the content of potassium, nicotine, total nitrogen, reducing sugar and total sugar, respectively, the ratio of sugar and nicotine and the ratio of sugar and nitrogen were 9. 10 and 7. 38, respectively; The Cd contents of lower leaves, middle leaves and upper leaves were 1. S7, 1. 37 and 1. 11 mg/kg, respectively, which was statistically lower the limit level of 3. 0 mg/kg prescribed by the China Tobacco Corporation. It was suggested that this fertilization scheme could be widely applied in various tobacco areas and similar producing areas of Liangshanyi autonomous prefecture. [ABSTRACT FROM AUTHOR]

(Objective] The purpose of this paper was to study the effects of buse and topdressing with different potassium-rich soil conditioners on tobacco production during the period of soil cultivation. [ Method ] In this study, wood peat derived potassium humate, mineral potash (hydrothermal method) and calcium magnesium phosphate fertilizer were used instead of KNOW, or K, SO, on the base, to study their effects on soil pH, available potassium, slow potassium, tobacco leaf quality and economic status of flue-cured tobacco. [ Result ] The results showed that base and topdressing different potassium-rich soil conditioners could effectively improve soil pH of tobacco root zone and keep it between 5.5 -6.5. The effect is as follows T5 > T3 > T4 > T2 > TI, among which wood peat derived potassium humate (base fertilizer) and calcium magnesium phosphorus fertilizer had the best effect; Topdressing wood peat derived potassium humate, mineral potash (hydrothermal meth od) and calcium magnesium phosphate fertilizer could significantly improve available potassium, slow potassium content of soil and the pro portion of middle, upper leaves'. Among them, woody peat derived potassium humate (basie fertilizer) and mineral potassium fertilizer (hydrothermal method) had the best application effect at 1:3. Compared with the control, the content of available potassium was increased by 60.95 % (0 - 10 cm),77. 78 % (20 -40 cm), the content of slow-acting potassium was increased by 16. 63 % (10. 20 peat derived potassium humate, mineral potash (hydrothermal method) and calcium magnesium phosphate fertilizer could ef province, increase soil potassium storage capacity and potassi um supply capacity, the proportion of upper and middle leaves, the quality of tobacco leaves and the economic situation of flue-cured toba co. Base woody peat derived potassium humate and topdressing mineral potassium fertilizer (hydrothermal method) have the best applicatic effect at 1:3. [ABSTRACT FROM AUTHOR]

[Objective ] The objective of the paper is to provide the scientific basis for reducing chemical fertilizer and improving efficiency for vegetable in acidic yellow soil area of Guizhou. [ Method] The effects of combined application of biochar and yellow phosphorus slag on yield and nutrient uptake and utilization of Chinese cabbage cultivated in acidic yellow soil are studied by a pot experiment in green house. [ Result] The yield of Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 37.22 % - 82.07% compared with that of non-fertilization treatment, and the yield of Chinese cabbage applied with chemical fertilizer + 70 glpot biochar + 11.7 glpot yellow phosphorus slag is the highest ( 553. 5 g/ pot) . The nitrogen, phosphorus and potassium content in Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 39.9% - 57.9%, 1.31% - 35.22% and 1.99 % -39.09% respectively compared with that of non-fertilization treatment. The nitrogen, phosphorus and potassium uptake of Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 107.8% - 188.9%, 65.89% - 128.82% and 61.73 % - 122.97% separately. Except there is no obvious difference in phosphorus uptake of Chinese cabbage applied chemical fertilizer + 18.0 glpot yellow phosphorus slag and non-fertilization treatment, the nitrogen, phosphorus and potassium uptake of Chinese cabbage under other treatments of biochar and yellow phosphorus slag combination is higher than that of nonfertilization treatment significantly. Among various fertilization treatment, chemical + 70 glpot biochar + 11.7 g/pot yellow phosphorus slag has the highest nitrogen and phosphorus utilization efficiency, respectively 59. 01 % and 8. 83 %, while chemical fertilizer+ 100 glpot biochar + 9.00 glpot yellow phosphorus slag has the highest potassium utilization efficiency, which is 92. 10 % . [Conclusion ] Rationally combined application of biochar and yellow phosphorus slag can improve yield, nutrient uptake and utilization of Chinese cabbage, and low amount of biochar combined with high amount of yellow phosphorus slag has the best effect. [ABSTRACT FROM AUTHOR]

The constant dynamic changes in salt pond make it difficult to achieve accurate prediction of ion concentration. It is of great significance to get the accurate prediction of potassium ion concentration in salt pools for the actual production of potash fertilizer. In this paper, some machine learning methods, such as support vector regression (SVR), AdaBoost regressor, K neighbor regressor, gradient boosting regressor, extra trees regressor and neural network regressor, have been used to build the prediction models. In the experiment, the MSE and R2 of the K+ concentration by using SVR in test data set reach 0.26385 and 0.9414, which are better than other models. Therefore, the SVR model has high research value in the field of salt pool ion concentration prediction. [ABSTRACT FROM AUTHOR]

The results of the field study with traditional mineral fertilizers and unconventional one, based on the processing of K-Mg ores, on seed potato planting are presented in this paper. The efficiency and aftereffect of potassium fertilizers (KCl and the processing product from clay-salt sludge) on the NP background were studied. The technology for the production of new fertilizer from clay-salt waste (sludge) remaining as a result of potassium fertilizers production from natural K-Mg ores, was elaborated in Mining Institute, the division of Perm Federal Research Center. The resulting product, containing K, Ca, Mg and trace elements, which has the properties of fertilizer and ameliorant, has received the name the cinder of clay-salt sludge. The main processes in the technology are waste enrichment and subsequent high-temperature calcination of the enriched concentrate. As a result, the product, with the properties of multiple slow-release fertilizer was formed on a chloride-free basis. It is undesirable to use for potato fertilizers containing chlorine, so it is useful to expand the range of potassium fertilizers. The field trials with cinder were fulfilled on the experimental plots of Perm Agricultural Scientific Research Institute, the division of Perm Federal Research Center, in 2018-2020 years. The experimental scheme included treatments: control (without fertilizers), NP - background; NP + KCl and NP + cinder. Potassium fertilizers were used in autumn (basic application) and in spring (pre-planting application). No fertilizers were used in 2020. The influence of mineral fertilizers on yield and quality of seed potato, as well as soil fertility parameters were studied. The obtained results showed that the direct effect of unconventional fertilizer (cinder) with its pre-planting application was approximately equal to the effect of traditional potassium chloride fertilization, provided that the rates in the active substance were equal (yield in 2019 - 46.0 and 47.1 t-1 ha, respectively). The use of cinder did not have a significant effect on the quality indicators of potato tubers both directly in the year of fertilization and after the storage period. Cinder, in contrast to the standard KCl fertilizer, had a positive effect on the content of exchangeable potassium in the soil. Research with unconventional mineral fertilizers based on K-Mg ore processing wastes should be continued with an emphasis on the study of long-term action as a complex ameliorant. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore suitable water and fertilizer integration with reduced fertilization mode for flue-cured tobacco production on slope land in southern tobacco-growing areas [Method] Taking the local conventional water and fertilizer management as a comparison, the effects of water and fertilizer integration on dry matter accumulation, N and K absorption and distribution, fertilizer utilization rate and soil nutrient balance of Hue-cured tobacco on slope land were studied. [ Result] Results of two-year experiment showed that the dry matter accumulation, nitrogen and potassium absorption of flue-cured tobacco with water and fertilizer integrated management were still higher than those of control when fertifu.er was reduced, and fertilizer utilization ratio significantly increased, and the nutrient surplus and balance coefficient were reduced. T2 treatment with 20 % reduced fertilization increased the dry matter accumulation by 22. 28 % in maturing stage than that of conventional treatment, and promoted the absorption of nitrogen and potassium by 92. 64 % and 83. 23 % respectively in root extending stage. The apparent utilization rate, season recycling rate and economic utilization rate of nitrogen fertilizer of T2 treatment increased by 20. 98 %, 14. 6 % and 8. 6 % respectively compared with CK, even 15. 25 %, 16. 15 % and 17. 64 % higher than Tl treatment with the same amount fertilizer. Fertilizer productive efficiency of potassium increased by 35. 02 % on average, and the biggest difference of apparent utilization rate, season recycling rate and economic utilization rate between T2 and CK appeared in 2017, reaching 80. 62 %, 105. 6 % and 126. 03 % . From the soil nutrient balance, water and fertilizer- integration mode increased crop carrying capacity and reduced nutrient surplus. Compared with CK, T2 and T3 treatments reduced nitrogen surplus by 49. 3 and 54. 6 kg • hm -2, and the nutrient balance rate decreased 93. 85 and 103. 16 percentage points. The best performance on potassium balance was T2 treatment, it's potassium surplus decreased by 86. 69 kg·hm-2 compared with CK, and the balance rate fell 158. 75 percentage points. [ Conclusion] In conclusion, under the water and fertilizer integration mode, it can improve the fertilizer utilization rate and reduce the soil nutrient surplus by properly reducing the fertilizer consumption and increasing the topdressing ratio. [ABSTRACT FROM AUTHOR]

( Objective) The present paper aimed to solve at the deterioration of soil physical properties and decline of soil fertility by irrational fertilization in northern Liaoning province, and the effects of different fertilization treatments on soil physicochemical properties and spring maize yield in northern Liaoning province were studied. [Method] Successive 2 year field experiments were conducted in the main maize production area in the northern of Liaoning. Five different treatments with mixed chemical and organic fertilizers no nitrogen with chemical P and K ( CK),conventional fertilization( CK1), optimize fertilization(T1), organic manure combined with chemical fertilizer(T2), and humic acid combined with chemical fertilizer( T3) with three replications were examined. The soil bulk density, soil nutrients, maize yield and yield components of each treatment were compared. [Result] The humic acid and organic mature combined with chemical fertilizer could reduce soil bulk density, compared to conventional fertilization treatment, decreased soil bulk density by 2. 97 % and 3. 94 %, 1. 22 % and 3. 08 %, 2. 67 % and 3. 60 % in 5 -10, 10 - 15 and 15 - 20 cm of soil layers. Compared to conventional fertilization, applying humic acid and organic manure could significantly improve soil fertility, increased organic matter by 2. 38 % and 2. 98 %, alkali-hydrolyzed nitrogen by 5. 69 % and 9. 82 %,available phosphorus by 14.47 % and 19. 60 % and available potassium by 8.07 % and 7. 92 %. The maize yield of humic acid and organic manure treatment was higher than that of the conventional fertilization treatment, respectively, increased by 950 and 852 kg/hm 2 • (Conclusion ) The comprehensive analysis results showed that the measures of suitable fertilization in northern Liaoning province was that the amount of humic acid was 600 kg/hm² or organic mature was 1500 kg/hm² while the nitrogen application was 198. 9 kg/hm². [ABSTRACT FROM AUTHOR]

[Objective] The effects of different nitrogen and potassium application amounts on NK nutrition utilization and yield of rapeseed on different soil types in rapeseed-tobacco rotation area was studied. The purpose of this paper was to provide theoretical basis and technical support for precision nutrient management and reducing chemical fertilizer of rapeseed production. [ Method] Field trials were carried out in 3 kinds of soil type to investigate yield and nutrition utilization of rapeseed with different nitrogen and potassium application amounts. Egression equations of the quadratic model between N and K application amounts and N and K nutrition utilization of rapeseed were established. The effects of different nitrogen and potassium application amounts on different soil types on yield of rapeseed was analyzed. [ Result] Yield of rapeseed with N 90 kg/hm² was the highest in red soil. Yield of rapeseed with N 180 kg/hm² was the highest in paddy soil. Yield of rapeseed with N 270 kg/hm² was the highest in sandy loam. The yield increasing effect of N was sandy loam > paddy soil > red soil. Contribution of N to yield was red soil > paddy soil > sandy loam. In red soil, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 63. 68 %,31. 53 % and 18. 59 % respectively. In paddy soil, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 54.95 %,42. 5 % and 29. 45 % respectively. In 8&l'ldy loam, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 31. 95 %,37. 14 % and 33. 29 % respectively. There was no significant difference in yield of rapeseed between treatment with K and no K. In paddy soil and in sandy loam, yields of rapeseed with K SO kg/hm² was higher than other treatments. The yield-increasing effect of K was red soil > paddy soil > sandy loam. Contribution of K to yield was red soil > paddy soil > sandy loam. In red soil, K use efficiencies of rapeseed with K 50, 100, 150 kg/hm² was 46. 52 %,30. 2 % and 28. 18 %, respectively. In paddy soil, K use efficiencies of rapeseed with K SO, 100, 150 kg/hm² was 38. 91 %,22. 89 % and 19. 61 %, respectively. In sandy loam, K use efficiencies of rapeseed with K 50, 100, 150 kg/hm² was 55. 6 %,31. 29 % and 18. 39 %, respectively. [ Conclusion] In red soil of Luoping City, application amount of N and K on rapeseed production should be reduced. In paddy soil of Chengjiang City, application amount of K on rapeseed production should be controlled. In sandy loam of Tengchong City, application amount of N on rapeseed production should be increased and application amount of K on rapeseed production should be controlled. It was important that different nutrient management strategy should be adopted on different soil types in different area. [ABSTRACT FROM AUTHOR]

【Objective】Through the comparison of models, the present paper aimed to explore the influence of ’chninese milk vent Returning to the Field coupled with rice and fish symbiosis’ on the soil nutrients and yield of rice, and provided a scientific basis for efficient and high-quality rice production and sustainable development.【Method】In this experiment, four treatments including conventional rice planting as a control(CK), chninese milk vent Returning to the Field(ZD), rice and fish symbiosis(YD),chninese milk vent Returning to the Field coupled with rice and fish symbiosis(ZY), measuring, analysis and comparison of the contents of soil nutrients(organic matter,total nitrogen, total phosphorus,total potassium and their effective state), rice yield and yield component index of each treatment were performed.【Result】Compared with CK, YD, ZD and ZY can effectively improve the soil fertility of rice in the current season, and ZY has the best effect. Compared with CK, soil organic matter, total nitrogen, total phosphorus, total potassium and their effective state content of ZY mature period were increased by 16.40 %, 18.18 %, 20.63 %, 3.42 %, 7.71 %, 15.96 % and 1.85 %(P<0.05); ZD can effectively alleviate soil acidification, and the soil pH at maturity was 6.06,which compared with CK, YD and ZY, it increased by 0.04, 0.12 and 0.08 units, and the difference was significant(P <0.05);Compared with CK,ZY, ZD, and YD can increase the yield of rice in the season effectively, and ZY has the highest yield of rice, reaching 6.29 t/hm~2. Compared with CK, ZD and YD, the actual yield of ZY increased by 4.83 %-11.33 %,and the difference was significant(P <0.05).【Conclusion】In summary, chinese milk vent returning to the field coupled with rice and fish symbiosis can effectively improve soil fertility and significantly increase rice production in the current season, which was an greenand efficient way of fertilizing. [ABSTRACT FROM AUTHOR]

[Objective] The objective of the paper is to provide the scientific basis for rational fertilization in Jianhe County of Guizhou Province and similar areas. [Method] The effects of soil nutrient indexes(total N .organic matter, available N .available K, available P, total P and total K)on soil fertility are explored by using variation coefficient method, correlation coefficient method and weighted mean method, and then the soil fertility in paddy field and dry' land is evaluated by using improved Nemerow comprehensive evaluation method combined with the weight coefficient mean value of the three methods. [Result] The soil available k in paddy field and total P in dry land were at a lower level, while other nutrient indexes were at a medium-high, high and higher level. The soil available N content in six dry' land sampling sites with different plants was high. Soil total P and available k fluctuate greatly among sampling sites, while organic matter content fluctuates less. The soil available P in fertility factor weighted coefficient of paddy field and dry land was the highest, respectively 0. 2710 and 0. 2358 comparing the mean value of the three weighted method weighted coefficient. The available P is the main factor influencing soil fertility in paddy field and dry' land and soil fertility indexes is 1.52 and 1.63 separately. The soil comprehensive fertility was at a fertile level. [Conclusion] The soil fertility of paddy field and dry land in Jianhe County is at a fertile level, and available P is the main factor influencing soil fertility in paddy field and dry land. The soil N content in paddy field and dry land is high, which can meet the demand of crop production. Therefore, N fertilization should be reduced in production. The soil K content in paddy field is low, and the corresponding fertilization measures should be taken to improve K supply level in paddy field. [ABSTRACT FROM AUTHOR]

China is one country in the world with the largest potash fertilizer-demand. Potash has been listed as one of the seven strategic resources in China for a long time. Qarhan Salt Lake is the earliest discovered large-scale potash deposit in China. It is a comprehensive deposit dominated by liquid potash resource with the coexistence of solid potash minerals (polyhalite, carnallite, sylvite) and other beneficial elements. It is the largest potash fertilizer production base in China. However, with the increase in production year by year, its potash reserves which reach industrial grade are decreasing continuously, and the sustainable production of potash fertilizer faces a severe reserve shortage. So it is particularly noteworthy to us that there are still 296 million tonnes of low-grade solid potash minerals in Qarhan Salt Lake, which have potential utilization value. These low-grade solid potash minerals are equivalent to a superlarge potash deposit. In this paper, we review the efforts to increase potash supply, to upgrade the industrial structures and to promote the healthy and sustainable development of the potash fertilizer industry in Qarhan Salt Lake, then discuss the process of exploitation and utilization of low-grade solid potash minerals, and the problems encountered, finally proposed the corresponding countermeasures suggestions. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to provide theoretical basis for the rational application of potassium and chlorine fertilizer in the flue-cured tobacco production in Yunnan raw material base of Yunyan brand.【Method】 1130 soil samples from 37 counties of Kunming, Qujing, Honghe, Baoshan, Wenshan were used as materials to determine the content of potassium and chlorine in tobacco samples. The characteristics of potassium and chlorine ratio in different regions, main varieties, soils at different altitudes and tobacco leaves in Yunnan raw material base of Yunyan brand were analyzed. The potassium chlorine ratio of tobacco leaves was regionalized by ArcGIS. 【Result】The results showed that the samples with potassium chloride ratio more than 10 % were the most, accounting for 43.2 %; The samples with potassium chloride ratio between 4.0 % and 6.0 % were the least, accounting for 11.7 %. Qujing had the largest number of towns with low K/C ratio(< 4 %) and Wenshan had the smallest; Qujing had the largest number of towns with high K/C ratio(> 10 %), while other cities had the same number. The main cultivar with the highest mean of K/C ratio in middle tobacco leaves was Yunyan 85, which was 14.41; The lowest was Yunyan 97, which was 7.30; The others were between 8.44 and 12.73. The highest mean of K/C ratio of middle tobacco leaves in different altitude areas was 11.72, which was mainly distributed in the altitude area of 1100-1400 meters; The lowest was 8.91, which was mainly distributed in the altitude area of 2000-2300 meters. 【Conclusion】In order to production of high-quality flue-cured tobacco in Yunnan raw material base of Yunyan brand, areas with high K/C ratio of tobacco leaves in Kunming, Qujing, Honghe, Baoshan and Wenshan could be selected. K326, Yunyan 87, Yunyan 85 and other high efficient flue-cured tobacco varieties for potassium accumulation and utilization could be selected. It could be planted at the altitude of 1100-2000 meters. [ABSTRACT FROM AUTHOR]

Farmland management measures can have a significant impact on the carbon cycle of farmland ecosystems, which can affect soil fertility, agricultural production, and food security, and more broadly, climate change and environmental health. In this paper, the effects of different farmland management measures（fertilization methods, planting systems, and farming models）on soil organic carbon, greenhouse gas emissions, and soil microorganisms were reviewed. The increase in soil organic carbon was fastest when organic and inorganic fertilizer were applied. Moreover, there was a threshold effect between the amount of fertilizer applied and the soil carbon inventory. The application of organic fertilizer increased the CO2 emissions flux in the soil, and the application of phosphorus and potassium fertilizers reduced the globe warming potential of farmland soil more than nitrogen fertilizer. Increasing the application ratio of organic fertilizer to phosphate fertil⁃ izer was beneficial, leading to an increase in microbial richness in the soil and accumulation of microbial biomass carbon. Planting struc⁃ ture and planting density both affected the carbon storage of farmland soil, and planting structure had a significant impact on greenhouse gas emissions in farmland ecosystems. Compared with traditional monoculture planting, crop rotation and intercropping could effectively re⁃ duce the greenhouse gas emissions of farmland. At the same time, crop rotation was more conducive to increasing soil microbial diversity than continuous cropping. Conservation tillage improved the efficiency of farmland soil carbon, reduced greenhouse gas emissions, and had a positive impact on microbial activity, diversity, community structure, and carbon source utilization. Finally, we summarized the applica⁃ tion of international mainstream carbon models to farmland ecosystems, and present future development prospects. [ABSTRACT FROM AUTHOR]

Agricultural ammonium nitrate(ANP) is one of the main raw materials for the production of AN-based compound fertilizer. The IV-III phase transition of ammonium nitrate(AN) is one of the main reasons for the caking of AN-based compound fertilizer(NPK). Potassium salts used for the production of compound fertilizers are usually K2SO4(KS). In this paper KNO3(KN) was added to improve the anti-caking properties of AN-based NPK. The IV-III phase transition of ANP and the effects of KN, KS, NH4SO4(NS), and NH4H2PO4(NP) on the solid phase transitions of ANP was investigated by differential scanning calorimetry (DSC) and powder X-ray diffractometer(XRD). The results showed that the phase transformation inhibition effect of KN and KS on ANP was better than that of NS and NP. In this experiment, KN was used to replace part of KS in the formula of AN-based NPK, and the granular fertilizer with different contents of KN were prepared, the anti caking properties and hygroscopicity of the fertilizer were tested. The results showed that although the content of potassium in the compound fertilizer remained unchanged, with the increase of the content of KN and the decrease of the content of KS in the formula, the anti-caking performance and hygroscopicity of the AN-based NPK were obviously improved. [ABSTRACT FROM AUTHOR]

Potassium (K) is one of three main crop nutrients, and the high rate of potash fertilizer utilization (second only to nitrogen) leads to high prices. Therefore, efficient application, as well as rapid and time monitoring of K in crops is essential. Several turnover box and field experiments were conducted across multiple years and cultivation factors (i.e., potassium levels and plant varieties) yielding 340 groups of leaf samples with different K contents; these samples were used to examine the relationship between reflectance spectra (350–2500 nm) and leaf K content (LKC). The correlation between LKC and the two-band spectral indices computed with random two bands from 350 to 2500 nm were determined for the published K vegetation indices in rice. Results showed that the spectral reflectance, R, of the shortwave infrared (1300–2000 nm) region was sensitive to the K levels and significantly correlated with rice LKC. New shortwave infrared two-band spectral indices, Normalized difference spectral index [NDSI (R1705, R1385)], Ratio spectral index [RSI (R1385, R1705)], and Difference spectral index [DSI (R1705, R1385)], showed good correlations with LKC (R2 up to 0.68). Moreover, the three-band spectral indices (R1705 − R700)/(R1385 − R700) and (R1705 − R1385)/(R1705 + R1385 − 2 × R704) were developed by adding red edge bands to improve accuracy. Three-band spectral indices had an improved prediction accuracy for rice LKC (R2 up to 0.74). However, several previously published K-sensitive vegetation indices did not yield good results in this study. Validation with independent samples showed that the indices (R1705 − R700)/(R1385 − R700) and (R1705 − R1385)/(R1705 + R1385 − 2 × R704) had higher accuracies and stabilities than two-band indices and are suitable for quantitatively estimating rice LKC. The widescale application of these proposed vegetation indices in this paper still needs to be verified in different environmental conditions. This study provides a technical basis for LKC monitoring using spectral remote sensing in rice. [ABSTRACT FROM AUTHOR]

[Objective] The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping. [Method] Two experimental treatments (i. e. decomposed organic fertilizer + biochemical fulvic acid potassium water soluble fertilizer, decomposed organic fertilizer + compound fertilizer) were designed to determine the changes in physical and chemical properties before and after soil treatment, and the survival rate, plant height and ground diameter of four different cultivated plants within one year, and the effects of applying biochemical fulvic acid potassium on cultivated plants were investigated. [Result] The soil organic matter, total nitrogen, alkali-hydrolyzable nitrogen, soil available phosphorus, soil available potassium and pH value in the soil treated with decomposed organic fertilizer + biochemical fulvic acid potassium soluble fertilizer, and decomposed organic fertilizer + compound fertilizer increased significantly, and the soil bulk density decreased obviously. The survival rates, plant heights and ground diameters of four different cultivated plants were significantly improved after application of decomposed organic fertilizer + biochemical fulvic acid potassium water soluble fertilizer, and decomposed organic fertilizer + compound fertilizer (P<0.05). [Conclusion] The application of biochemical fulvic acid potassium on cultivated plants effectively improved soil fertility, increased the utilization of nitrogen, phosphorus and potassium, improved the growth of plants, and promoted the growth of landscaping plants after transplantation. [ABSTRACT FROM AUTHOR]

The accumulation of heavy metals (HM) in agricultural soils leads to an increased uptake by plants. This affects food quality and safety. This paper reports experiments on the effects of nickel (Ni) applications and soil moisture conditions (SMC) on Ni, nitrogen (N), phosphorous (P), potassium (K) and sodium (Na) concentrations and the uptake by canola in two different soil textures. The average translocation factors (TF) of canola under water deficit conditions were higher than those under normal conditions. In general, canola has weak ability to translocate Ni towards the aboveground parts of the plant. This point may be useful in the application of fertilisers to the soils when canola is planted or in the phytoremediation of Ni-polluted soils. [ABSTRACT FROM AUTHOR]

[Objective] This paper aims to provide optimal fertilization guidance for high-yield cultivation of P. frutescens and promotion of new P. frutescens varieties. [ Method] The effects of nitrogen, phosphorus and potassium fertilizers on the yield of two new P. frutescens varieties ( Qisu 2 and Qisu 3) were studied by ternary quadratic orthogonal rotation design. The regression equation and model analysis were constructed to optimize the high-yield fertilization mode. [ Result] N was the most important factor influencing the yield of P. frutescens. However, the two varieties varied in response to P and K fertilization. The regression models of nitrogen (x1) , phosphorus (x2) and potassium (x3) of the yield (Y) are Y = 2219.384 + 405.410x1, +304.926x2 - 156.723x12 -78.676x22 - 214. 479x1x2, and Y =2048.806 + 319.535x1, +54.722x3 -63. 102x12 - 113. 664x22 +76.017x32 -69.069x1x2, respectively. The best fertilization ratio of N, P and K fertilizer was (286.022 ±25.288),(139.059 ±20. 819),(180. 000 ± 35. 860) kg/hm2 , and (338. 180 ± 16.617) , (80. 923 ±21.314) , (203.529 ± 24. 278 ) kg/hm2, respectively. The yield of P. frutescens could reach 2250 kg/hm2. [ Conclusion ] Compound application of NPK fertilizers functioned significantly in enhancing P. frutescens yield. [ABSTRACT FROM AUTHOR]

[Objective]This paper aimed to study the selenium contents in soil and tea leaves at different planting year tea trees( la, 5a, 10a, 15a). [ Method] Field sample investigation and indoor analysis method were measured. [ Result] (i) The crown, stem and branch of tea trees increased and tree density decreased with increasing planting age. (ii) Soil nutrients (Organic carbon, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus and available potassium) first increased and then decreased from 1 to 15 years of tea trees, which showed 10 a > 15 a >5 a > 1 a. (iii) Water extract, tea polyphenols, caffeine and free amino acids first increased and then decreased from 1 to 15 years of tea trees, which showed 10 a > 15 a >5 a > 1 a. (iv) Total selenium content, total selenium enrichment coefficient and effective total selenium enrichment coefficient in soil and tea first increased and then decreased from 1 to 15 years of tea trees, which showed 10 a > 15 a >5 a > 1 a. (v) Correlation analysis showed that the total selenium content in soil was significantly positively related with soil nutrient, and there was the correlation of the tea full selenium and effective selenium with soil physical and chemical properties but not significant (P > 0.05). [ Conclusion ] The main influencing factors for soil selenium were organic carbon (load coefficient was 0. 689) and total nitrogen (load coefficient was 0.702) , and the main influencing factors for the selenium of leaves were the water extract of tea ( load coefficient was 0. 623 ) and tea polyphenols (load coefficient was 0.726). [ABSTRACT FROM AUTHOR]

An improved ability to predict pasture dry matter (DM) yield response to applied phosphorus (P), potassium (K) and sulfur (S) is a crucial step in determining the production and economic benefits of fertiliser inputs and the environmental benefits associated with efficient nutrient use. The adoption and application of soil testing can make substantial improvements to nutrient use efficiency, but soil test interpretation needs to be based on the best available and most relevant experimental data. This paper reports on the development of improved national and regionally specific soil test–pasture yield response functions and critical soil test P, K and S values for near-maximum growth of improved pastures across Australia. A comprehensive dataset of pasture yield responses to fertiliser applications was collated from field experiments conducted in all improved pasture regions of Australia. The Better Fertiliser Decisions for Pastures (BFDP) database contains data from 3032 experiment sites, 21 918 yield response measures and 5548 experiment site years. These data were converted to standard measurement units and compiled within a specifically designed relational database, where the data could be explored and interpreted. Key data included soil and site descriptions, pasture type, fertiliser type and rate, nutrient application rate, DM yield measures and soil test results (i.e. Olsen P, Colwell P, P buffering, Colwell K, Skene K, exchangeable K, CPC S, KCl S). These data were analysed, and quantitative non-linear mixed effects models based upon the Mitscherlich function were developed. Where appropriate, disparate datasets were integrated to derive the most appropriate response relationships for different soil texture and P buffering index classes, as well as interpretation at the regional, state, and national scale. Overall, the fitted models provided a good fit to the large body of data, using readily interpretable coefficients, but were at times limited by patchiness of meta-data and uneven representation of different soil types and regions. The models provided improved predictions of relative pasture yield response to soil nutrient status and can be scaled to absolute yield using a specified maximal yield by the user. Importantly, the response function exhibits diminishing returns, enabling marginal economic analysis and determination of optimum fertiliser application rate to a specific situation. These derived relationships form the basis of national standards for soil test interpretation and fertiliser recommendations for Australian pastures and grazing industries, and are incorporated within the major Australian fertiliser company decision support systems. However, the utility of the national database is limited without a contemporary web-based interface, like that developed for the Better Fertiliser Decisions for Cropping (BFDC) national database. An integrated approach between the BFDP and the BFDC would facilitate the interrogation of the database by advisors and farmers to generate yield response curves relevant to the region and/or pasture system of interest and provides the capacity to accommodate new data in the future. Optimising phosphorus, potassium and sulfur fertiliser applications to pasture will improve the productivity of grazing industries as well as environmental outcomes. The compilation and utilisation of extensive national field studies has enabled soil test interpretation to be based on the best available and most relevant experimental data. The derived critical soil test P, K and S targets have improved fertiliser recommendations for improved pastures in Australia. [ABSTRACT FROM AUTHOR]

[Objective] The aim of this paper was to provide a theoretical relerence for the application of loss-control urea in rice production in yellow soil. [Method] Based on the same application rates of phosphorus and potassium fertilizer, the rice cultivar Leyou 58 was employed to explore the ellects of loss-control urea, with various adding amount of loss-control agent (1 %,2%,3%,4%,5%,6%), on rice yield, nutrients uptake and utilization. Meanwhile, no nitrogen and common urea fertilizer were taken as the controls. [Result] No regular changes of rice yield observed with increasing the dosage of loss-control agent, while the accumulation of nitrogen in rice grain, nitrogen, phosphorus and potassium in rice straw, and potassium in aboveground parts showed regular variation. At the same time, regular changes were also observed on rice nitrogen, phosphorus, potassium harvest index and potassium absorption efficiency. Compared with common urea treatment, six kinds of loss-control urea with the loss-control agent of 1 % -6 % could increase the rice yield in some degree, among which 1 % adding amount performed the best. The yield increasing rate was up to 12.22 %. The adding amounts of 1 % , 2 % and 6 % enables absorption of nitrogen, phosphorus, potassium by rice and accumulation in the rice seeds sufficiently to promote the yield and quality of rice. The adding amount of 3 % enhanced the accumulation of nitrogen, phosphorus and potassium in rice straw, increased the resistance and promoted the growth. [Conclusion] To sum up, the effect of urea with 1 % loss-control agent performed the best in rice production. [ABSTRACT FROM AUTHOR]

Multiple interactions between different species in the potash flotation. As the main resource of potash fertilizer, high grade of sylvite (KCl) is mainly separated from halite (NaCl) in soluble potash ores using flotation. An effective flotation collector determines the separation efficiency of sylvite. However, the collector adsorption mechanism is still the subject of much debate due to high ions concentration in the flotation pulp. This paper studies the hydration status of KCl, the flotation behavior of KCl and NaCl with lauric acid and the interfacial water structure of the soluble salts to provide further insights into the fundamental mechanisms at play. The contact angle measurements and laboratory micro-flotation experiments have shown that both the hydration status of KCl and the flotation soluble salts with lauric acid were dependent on the solution composition. Specifically, it was determined that the addition of Na-ions had an adverse effect on the hydrophobicity of KCl crystals. Both KCl and NaCl can be floated with lauric acid. However, flotation of NaCl is greatly enhanced with the addition of K-ions whereas the flotation of KCl is suppressed with the addition of Na-ions. Sum frequency generation (SFG) measurements have found, most strikingly, more disordered water molecules dominating the "structure maker" salt surfaces in a saturated NaCl solution. "Collins Concept" is employed to explain the specific ion binding behaviors in the flotation pulp. [ABSTRACT FROM AUTHOR]